It is advantageous for unleaded fuel compositions to meet the CARB Phase 3 model. 13 CCR §§2657-2273 (last updated January, 2010) esp. 13 CCR §2265. Among other things, the CARB Phase 3 model specifies a temperature at which 50 vol. % of the unleaded fuel composition vaporizes, a “T50 (maximum)”, of 104.4° C. (220° F.), and a temperature at which 90 vol. % of the unleaded fuel composition vaporizes, a “T90 (maximum)” of 165.6° C. (330° F.) (both measured using ASTM D-86-10a (1999)).
It is also advantageous for the pump octane rating of the fuel to be high enough to prevent knocking. Gasolines sold at service stations typically have a pump octane rating of from about 87 to about 93. Fuels exhibiting such pump octane numbers are satisfactory for most automotive engines. For high performance engines, and for racing engines in particular, fuels having even higher pump octane ratings are needed.
The production of fuels of progressively higher pump octane ratings is progressively more difficult to achieve. In particular, fuels exhibiting a pump octane rating at or above 100 are highly desired and the most difficult to produce. This is particularly true for unleaded fuels.
Unfortunately, commercially available unleaded fuels that meet the CARB Phase 3 model and exhibit a pump octane rating of 93 or more tend to exhibit lower average torque output values and lower average power output values than may be desirable for high performance fuels.
A need exists for high octane unleaded fuel compositions that meet the CARB Phase 3 model and that have higher average torque outputs and/or higher average power outputs.